Drawable sulphur resistant can coating

Abstract

Disclosed is a coating system for use in connection with a ferrous plate to be drawn into containers for packing sulphur bearing foods. More particularly, the coating system is capable of being drawn and includes aluminum and zinc oxide for purposes of uniform interior appearance and sacrificial protection respectively.

What is claimed: 
     
       1. A coating system for the inside of a drawn container for carrying sulphur bearing foods including a blank to be drawn into a container having applied thereover an epoxy phenolic primer base coat containing aluminum pigmentation being a relatively small fraction by weight of resinous solids therein and a top coating applied thereover being an oleo resinous material having zinc oxide powder being a relatively small fraction by weight of solids therein.   
     
     
       2. The coating system of claim 1 wherein the aluminum pigmentation is 10% by weight of the resinous solids. 
     
     
       3. The coating system of claim 1 wherein the zinc oxide powder is in the range of 15 to 30% by weight of the solids in the oleo resinous material. 
     
     
       4. The coating system of claim 1 wherein the oleo resinous material is a heat polmerized olefinic structure. 
     
     
       5. The coating system of claim 1 wherein the oleo resinous material is a heat cured oxidized and crosslinked polyester structure. 
     
     
       6. A method of coating a metal plate to be drawn including the following steps: (a) applying by roller coating an epoxy phenolic primer base coat carrying aluminum pigmentation of about 10% of the weight of solids therein to a ferrous substrate;   (b) curing said epoxy phenolic coating at about 400° F. for 6 to 10 minutes in a hot air convection oven;   (c) applying by roller coating a top coating of oleo resinous material carrying 15 to 30% by weight of solids therein of zinc oxide powders, and   (d) curing said oleo resinous top coating in an air convection oven for 6 to 10 minutes at about 415° F.   
     
     
       7. A drawable sulfur resistant coating system on the inside of a drawn container fabricated for packing processable sulphur bearing comestibles including an epoxy phenolic primer base coat applied by roller coating at a rate of 17 mg per 4 square inches and having aluminum pigmentation of about 10% by weight of the solids therein, said base coating being cured by heat in a hot air convection oven for 6-10 minutes at 400° F. and a top coating which is applied by roller coating at a rate of 22 mg per 4 square inches thereover and being an oleo resinous vehicle with zinc oxide powder being about 15-30% by weight of solids therein and cured at 415° F. in an air convection oven for 6-10 minutes. 
     
     
       8. The coating system of claim 7 wherein said oleo resinous vehicle is a heat polymerized olefin structure. 
     
     
       9. The coating system of claim 7 wherein said oleo resinous vehicle is a heat oxidized and crosslinked polyester structure. 
     
     
       10. The coating system of claim 7 wherein said container has sulphur bearing comestibles and the zinc oxide in the coating neutralizes odorous sulphur compounds in the volatile head space gases.